Centerless grinding machine



Jan. 22, 195? w. STAHLECKER ET AL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet l'LJILHELM STAHLECKER AND HANS RH-L 1957 w. STAHLECKER ET AL 65CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 2L/ILHELM STAHLaKe-R AND HANS @RLL 1957 w. STAHLECKER ETAL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 3INVENTORI Wdheflm sfqhleckek 1957 w. STAHLECKER ETAL 2,778,165

CENTERLESS GRINDING MACHINE Filed Nov. 30, 1953 4 Sheets-Sheet 4 andBy.- HMII 6m! 2,7 7 8,165 CENTERLESS GRINDING MACHINE WilhelmStahlecker, 'Iuhingen, and Hans Grill, Sussen, Germany ApplicationNovember 30, 1953, Serial No. 395,241 Claims priority, applicationGermany December 6, 1952 9 Claims. '(Cl. 51-103) purposes, but also ofobjects of conical, convex, and similar shapes.

More specifically, it is an object of the invention to devise a machinefor grinding roller-shaped bodies or similar objects to various shapes,wherein such objects are rotatably mounted by their axles, studs orhearing pins in a stirrup or bracket which, in turn, is pivotable in alldirections about a certain point distant from the axis of the objects soas to automatically with theiraxes parallel driving. means thereof.

It is a further object of the invention to provide a machine of the typedescribed with additionalmeans for positively moving the objects tobeground in certain directions about the pivotal point of their guidingbracket .so as to permit these objects to be ground either to "anaccurate cylindrical shape, a conical shape, or a convex shape.

Conical surfaces may possibly be ground. on substantially cylindricalobjects by adjusting the rotary axis of the driving roller relative tothe axis of the grinding wheel so as to extend at an angle thereto whichcorresponds to the desired angle of the conical surface to be ground.However, such driving mechanism "has the disadvantage of being rathercomplicated as well as expensive in manufacture since it would requirethat the entire heavy driving roller be pivoted from its normal positionto the axis of the [parallel with the axis of the grinding wheel to suchinclined position, preferably even without interruption of permit theobjects to adjust themselves.

its driving action while such adjustment is being carried out.

It has now been found according to the invention that, even though thedriving roller extends parallel with the axis of the grinding wheel,conical surfaces may also be ground on previously cylindrical objects byguiding the bracket, on which the object is mounted and which ispivotable in all directions at a point remote from such object, so as toallow the object, aside from its rotation about its own axis, movements.7

Accordingly, it is afeature of the invention to provide means forguiding the object to be ground so as to be only certain independentpivotal "independently movable, aside from the rotation about its ownaxis, only in a circular direction about the pivotal point of thebracket carrying the same within a plane passing through such pivotalpoint and extending at a right angle to the axis of said body, as wellas about an axis extending within such planeand connecting the axis ofthe object to be ground with the pivoting point of "the bracket.

the body to be and for this purpose it may be provided with means for"shifting it laterally,

the direction shown by the shaped-body '2 which is to be ground in thethe guiding bracket 5, whereas the two ends of carrying the half-she'lls-d, as well as the opposite end 'of I 2,778,165 Federated Jan. 22, 1957According to another feature of the invention, the

bracket may, aside from such independent movementof ground, also begiven a positive movement,

so as to enable the grinding not only of slightly conical surfaces, butalso of convex surfaces without requiring any adjustment of the axis ofthe driving roller to be'made. l

*Further'objects, features, and advantages of the present invention willappear from the following detailed description of several embodimentsthereof and the appended drawings, in which I Fig. 1 is a side view of agrinding machine according to the invention, which is provided with astirrup or bracket for supporting and guiding a roller-shaped body, andwhich includes a new mechanism for shifting such body from its normalcentral position toward one side, so

as'to permit grinding of .a conical surface thereon; #Fig. 2 is :a topview'of the grinding machine shown in Fig. l;

Fig. 3 is a view similar to Fig. 2, but only showing a *Fig. fiis a viewsimilar to "Fig. 3, in which the body to be ground is-disp'osed at anangle relative to the axis of the-driving roller for grinding a conicalsurface on body; 1 Fig. 5 is a side view of a -to another 'embodimentofthe invention, in which two rollers may be ground "simultaneously, andwherein the bracket for supporting and guiding said bodies may beshifted laterallyyby means of an eccentric lever or pin;

,7 Fig. 6 is a front view of the roller-shaped bodies to be "ground by amachine as shown in Fig. 5, and as seen in A arrow VI of Fig. 5;

Fig. 7 is a top view of the grinding machine shown in Fig. 5

Pig. 6 is a side view of. a grinding machine similar to 5, but providedwith a mechanism for that shown in Fig. ele'ctromagnetically arrestingthe lateral movement of the V guiding bracket; 1

Fig. 9 is aside view similar to Fig. 8 and showing a tracer forcontrolling-the electromagnet;

Fig. 1 0 is a top view of a grinding machine according to a furtherembodiment of the invention;

Fig. 11 is a partly sectional side view of another emgrinding machineaccording to the inven- Fig. 12 is a top view of the embodiment shown inAs shown particularly in Figs. 1 and 2 of the drawings,

The rollermachine is rotatablysupported on an axle 6 by means of twosets of ball bearings 7. The two projecting end portions of the axle ;6are halfway embraced from above by halfshells '8 which are secured to astirrup or fork 9 at one zontal axis ona suitable machine frame.

-end'o f'a guiding bracket 5. The other end of the bracket 5 carries aball ,4 which is supported in a ball cup 11 which is fixed to the frameof the machine. As shown especially in Fig. 1, the main portion of thefork 9 extends substantially in the same plane as the central portion ofthe fork 9 the bracket 5 carrying substantially at a part.

Thus, the guiding bracket 5 :tically as *wellas laterally,

the ball 4, are bent downwardly right angle relative to such centralwould be able to pivot verexcept for the provision ofia grinding machineaccording guiding element 12 which prevents the bracket from pivotinglaterally in a direction parallel to the horizontal plane passingthrough the ball and socket joint 4, 11. The guiding element 12 isslidably adjustable on a rail 13 on the machine frame in a directionsubstantially parallel with the axis of the driving roller 1; and may befixed thereto by means of a thumb screw or the like. To ensure adequatefrictional engagement between the driving roller 1 and the body 2necessary for driving the latter, a suitable weight is suspended on thecentral part of the bracket 5. As indicated in Figs. 5, 7, and 8,suitable means may be provided to adjust the position of the weight 15in longitudinal direction of the bracket 5 so as to vary the pressure ofthe body 2 upon the driving roller 1.

in the position shown in Figs. 1 to 3, the guiding element 12 is securedat the central point of the rail 13, so that the body 2 to be ground inthe machine will extend parallel with the driving roller 1 as well aswith the rotary axis of the grinding wheel 3, the driving and supportingelements of which are not shown in the drawings. Thus, when the grindingwheel 3 is driven in contact and shifted in a direction parallel to theaxis of the body 2, the latter will be ground to an accurate cylindricalshape.

In the position of the various elements shown in Fig. 4, the guidingelement 12, together with the bracket 5, is shifted slightly laterallyfrom its central position on the rail 13 so as to maintain theroller-shaped body 2 at a slight inclination relative to the grindingwheel 3. 'Thus, as shown in Fig. 4, the formerly cylindrical body 2 maybe ground to a slightly conical shape, the angle and direction of suchcone depending upon the amount or degree which the guiding element 12 isshifted laterally from its central position toward one end'or the otherof the rail 13.

Figs. 5, 6, and 7 of the drawings illustrate a grinding machineaccording to the invention which permits two roller-shaped bodies 2 tobe ground simultaneously. The two bodies are rotatably mounted on acommon axle 6 and are depressed by the guiding bracket 19 by means of ahalf-shell 28 fitted from above upon the central part of the axle 6intermediate the two ends thereof carrying the two bodies 2. Thehalf-shell 28 is provided'with two upwardly extending arms 28' havingvertical slots 32 therein. The guiding bracket 19 is operativelyconnected to shell 28 intermediate the said arms 28' by means of pins 29fixed to bracket 19 and extending into the slots 32 so as to allow acertain movement of the member 28 relative to the bracket 19. The latteris further provided at its forward end with a small central knife edge14 (Fig. 6) which transmits the pressure produced by the weight 15 uponthe axle 6 and the roller-shaped body or bodies 2, and permits minortilting or pivoting move ments of the axle 6 about the knife edge 14.

The rear end of the guiding bracket 19 is connected bymeans of auniversal joint on a bar 20, which is secured to or forms a part of themachine frame, so as to permit both vertical as Well as lateral pivotalmovements of the bracket 19. Such universal joint may, for example,consist of a central member 21 which is rotatably mounted on the bar 2%and pivotable about a vertical axis on two pins 18 within the bifurcatedend of the bracket 19. Two rings 22 secured to the bar at opposite sidesof the member 21 prevent the latter from sliding laterally there- Thelateral pivotal movements of the guiding bracket 19 are positivelycontrolled by an eccentric member 16 which is rotatably secured by meansof a shaft 31 in a art t its upper end which engages in a slot 34extending longitudinally of the bracket 19. The eccentric pin 30 mayeither be fixed to the member 16, or suitable meanes may be provided toadjust the amount of its eccentricity relative to the shaft 31. Thus, byrotation of the shaft 31 by suitable driving means which are not shownin the of the machine frame and has an eccentric pin 30 either manually,

. able tracer may be provided which may act upon,

, projection 38 fixed to drawings, the eccentric movement of the pin 30in the slot 34 is transmitted to the bracket 19 to pivot the samelaterally about its pivotal axis 18 to carry out a reciprocatorymovement for rounding oil the bodies 2 toward their opposite outeredges. Thereafter, if desired, the position of the roller-shaped bodies2 on the axle 6 may be reversed, so as to permit grinding of the twoother ends and to obtain evenly convex outer surfaces thereon.Obviously, the means above described for reciprocating the guidingbracket may also be provided in the embodiment of the invention shown inFigs. 1 to 4, in which event a convex surface may be ground on therollershaped body 2 in one continuous operation and without requiringany reversal of such body on the axle 6.

The machine shown in Figs. 5 to 7 may be used not only for grindingconvex bodies, as above described, but also for producing cylindrical orconical rollers. For producing cylindrical rollers, the rotary movementof the shaft 31 is stopped and the eccentric pin 30 is turned so as tobe in the central or neutral position, as shown in Fig. 7, whereupon thethumb screw 17 is tightened to lock the pin 30 in such neutral position.The same procedure is applied for producing slightly conical bodies,except for the fact that in such a case the required conical angle isadjusted by turning of the eccentric pin 30 toward one side or theother, and by then locking of it in such position by the thumb screw 17.

The grinding machine according to the embodiment of the invention shownin Fig. 8 corresponds in most details to that shown in Figs. 5 to 7,except for the fact that in place of the eccentric 30, 31 the guidingbracket 25 may be adjustably secured by means of an electromagnet 26which, when energized, is adapted to hold a plate 27 with two upwardlyextending arms 24 in a fixed position thereon. A transverse pin in thebracket 25 slidably engages in the slots 35 in the arms 24. As may beseen in Fig. 8, the slots 35 extend along the arc of a circle, thecenter of which coincides with the center of the bar 20 about which thebracket 25 is able to pivot in a vertical direction. Thus, when thecurrent is connected to energize the magnet 26, the plate 27 is securedin a fixed position either centrally on the magnet 26 to producecylindrical rollers or toward the front or rear, as viewed in Fig. 8, toproduce slightly conical bodies, and it thereby prevents any lateralmovement of the bracket 25 without, however, affecting its verticalmovement or its slight tilting movement. Also, the machine illustratedin Fig. 8 may additionally be provided with an eccentric mechanism,similarly as shown in Figs. 5 and 7, for producing convex bodies, inwhich event the magnet 26 is disconnected to allow the plate 27 to slideloosely thereon.

The magnet 26 may be connected or disconnected semiautomatically, orfully automaticalsuch automatic control of the magnet 26, a suitor beacted upon by, the grinding wheel or cylinder 3, as shown in Fig; 9.Referring to Fig. 9, it will be seen that the lever 37 is turnable aboutthe stationary pivot pin 39 and carries at its lower end a femaleelectrical plug member adapted to cooperate with the male electricalplug member 36 fixed to a stationary part of the machine as indicated inFig. 9. The spring 40 urges these plug members into operative engagementwith each other, as shown in the solid line position of lever 37, so asto energize the electromagnet 26 and to maintain the plate 27 in apredetermined angular position. When the grinding operation has beencompleted, the grinding wheel 3 is moved in a known manner away from theworkpiece 2 to the dotted line position shown at 3 in Fig. 9, and a abearing for the grinding wheel engages the top end portion of lever 37during movement of the grinding wheel to its inoperative position toturn the lever 37 in a counterclockwise direction about pin 39, asviewed in Fig. 9, so as to separate plug members 36 and 36' and thusopen the circuit to the electromagnet to ly. For

the eccentric shaft 30 deenergize the latter. Thus, the electromagnet 26is automatically energized when the grinding wheel is in its operativeposition engaging the workpiece and is autoinatica lly deenergized whenthe grinding wheel 3 is moved to rts inoperative position.

In place of the grinding or, In a tandem arrangement as shown in Figs. 5to 8, a separate grinding wheel may be provided for each of the bodiesto be ground, as shown in Fig. 10.

c The structure described above and shown in Figs. l-8 is capable ofproviding slightly conical or slightly spheriin Figs. 11 and 12. As isshown in Figs. 11 and 12, the bracket 19 and the driving roller 1 areturned simultaneously through the same For this purpose the drivingroller 1 is turnably which is turnable about its stationary pivot pin 46which is coaxial with the pivot'pi'ns 18. Turning movement of bracket 19and tape 42, as well as the bearings 41 for the roller 1 therewith, isproduced by which is common to elements 19 and 42. This shaft 30 extendsfreely through an elongated flap 43 formed in plate 42 as well as intothe slot 34 of bracket 19, and as was described above, shaft 31 togetherwith disc 16 may be turned to rotate the shaft about the axis of shaft31 so as to reciprocate the shaft 6 and the workpiece 2 carried therebyabout the common extending between pulleys respectively connected to themotor and driving roller. Motor 47 can be very small since only a smallamount of energy is required to drive roller 1 and workpiece 2.

When the claims recite an axle for rotatably mounting the bodies to beground on the machine, it is to be expressly understood that this termis to include an axle as well as bearing pins or studs which are eitherfixed to the respective body and projecting from at least one endthereof, or on which the respective body is rotatably mounted andsecured from sliding in axial direction thereof.

While we have described our invention with reference to severalpreferred embodiments thereof, we wish it to be understood that ourinvention is in no way limited to the details of such embodiments but iscapable of numerous modifications within the scope of the appendedclaims.

What we claim is:

1. Centerless grinding machine for grinding" a substantially cylindricalbody having an axle protruding from said body comprising in combinationa frame, a driving roller mounted substantially horizontally on saidframe and adapted to drive said cylindrical body by frictionalengagement therewith when said body is placed on top thereof, means fordriving said roller, a grinding wheel, means for rotatably mounting anddriving said grinding wheel, means for placing said grinding wheel inengagement with said body so as to grind the outer surface thereof, abracket, means at one end of said bracket for pivotally mounting thesame on said frame so as to be pivotable in various directions, at leastone half-shell of a bearing secured to the other end of said bracket andadapted to partly embrace said axle from above, means acting upon saidbracket for pressing said half-shell upon said axle to press said bodyupon said driving roller so as to be driven thereby, and means forrestraining said bracketfrom moving in at least one direction about saidpivotal mounting means so that the body to be ground, aside fromrotating about its own axis, can move independently only in a circulardirection about the pivoting point of said bracket within a planepassing through said pivoting point and extending at a right angle tothe axis of said body, as well as about an axis lying within said planeand substantially connecting the axis of the body to be ground with saidpivoting point.

'2. Centerless grinding machine as defined in claim 1, furthercomprising means for positively moving said bracket laterally about itspivoting point within a substantially horizontalplane, and means forarresting said lateral movement of said bracket in any position withinsaid horizontal plane.

3. In a centerless grinding machine, in combination, a driving rolleradapted torotate about a stationary axis coincident with its'own axis; ashaft located over and being substantially parallel to said roller forrotatably supporting a workpiece in engagement with said roller, wherebythe workpiece may be rotated by said roller and ground by a grindingwheel engaging the workpiece; and means engaging said shaft forconstraining the same to turn about a first turning axis parallel tosaid stationary axis and spaced from said roller and shaft and forturning said shaft about a second turning axis normal to said firstturning axis and substantially parallel to an axis normal to and passingthrough the axes of said roller and shaft.

4. In a centerless grinding machine, in combination, a driving rolleradapted to rotate about a stationary axis coincident with its own axis;a shaft located over said driving roller for rotatably supporting aworkpiece in engagement with said roller, whereby the workpiece may berotated by said roller and ground by a grinding wheel engaging theworkpiece; and means engaging said shaft for-constraining the same toturn about a first turning axis parallel to said stationary axis andspaced from said roller and shaft, for turning said shaft about a secondturning axis normal to said first turning axis and substantiallyparallel to an axis normal to and passing through the axes ofsaid rollerand shaft, and for guiding said shaft for tilting movement about a thirdturning axis which is parallel to an axis normal to said first andsecond turning axes and passing through the intersection therebetween.

5. In a Centerless grinding machine, in combination, a driving-rolleradaptedto rotate about a stationary axis coincident with its own axis; ashaft located over said driving roller for rotatably supporting aworkpiece in engagement with saidgroller, whereby the workpiece may berotated by said roller and ground by a grinding wheel engaging theworkpiece; means engaging said shaft for constraining the same to turnabout a first turning axis parallel to said stationary axis and spacedfrom said roller and shaft and for turning said shaft about a secondturning axis normal to said first turning axis and substantiallyparallel to an axis normal to and passing through the axes of saidroller andshaft; and means for releasably fixing said shaft in apredetermined angular position with respect to said second turning axis.

6. Centerless grinding machine for grinding a substantially cylindricalbody having an axle protruding from said body comprising, incombination, a frame; a driving roller mounted substantiallyhorizontally on said frame and adapted to drive the cylindrical body byfrictional engagement therewith when the body is placed on top thereof;means for driving said roller; a grinding wheel; means for rotatablymounting and driving said grinding wheel; means for placing saidgrinding wheel in engagement with the body so as to grind the outersurface thereof; a bracket; means at one end of said bracket forpivotally mounting the same on said frame so as to be pivotable invarious directions; at least one half-shell of a bearing secured to theother end of said bracket and partly embracing said axle from above;means acting upon said bracket for pressing said half-shell upon saidaxle to press the body upon said driving roller so as to be driventhereby; means for restraining said bracket for moving in at least onedirection about said pivotable mounting means so that the body to beground, aside from rotating about its own axis, can move independentlyonly in a circular direction about the pivoting point of said bracketwithin a plane passing through said pivoting point and extending at aright angle to the axis of the body, as well as about an axis lyingwithin said plane and substantially connecting the axis to be groundwith said pivoting point; and eccentric means for positively moving saidbracket laterally about its pivoting point within a substantiallyhorizontal plane.

7. Ccnterless grinding machine for grinding a substantially cylindricalbody having an axle protruding from said body comprising, incombination, a frame; a driving roller mounted substantiallyhorizontally on said frame and adapted to drive the cylindrical body byfrictional engagement therewith when the body is placed on 'top thereof;means for driving said roller; a grinding wheel; means for rotatablymounting and driving said grinding wheel; means for placing saidgrinding wheel in engagement with the body so as to grind the outersurface thereof; a bracket; means at one end of said bracket forpivotally mounting the same on said frame so as to be pivotable invarious directions; at least one half-shell of a bearing secured to theother end of said bracket and partly embracing said axle from above;means acting upon said bracket for pressing said half-shell upon saidaxle to press the body upon said driving roller so as to be driventhereby; means for restraining said bracket for moving in at least onedirection about said pivotable mounting means so that the body to beground, aside from rotating about its own axis, can move independentlyonly in a circular direction about the pivoting point of said bracketwithin a plane passing through said pivoting point and extending at aright angle to the axis of the body, as well as about an axis lyingwithin said plane and substantially connecting the axis to be groundwith said pivoting point; and eccentric means for reciprocating saidbracket laterally about its pivoting point within a substantiallyhorizontal plane.

8. Ccnterless grinding machine for grinding a substantially cylindricalbody having an axle protruding from said body comprising, incombination, a frame; a driving roller mounted substantiallyhorizontally on said frame and adapted to drive the cylindrical body byfrictional engagement therewith when the body is placed on top thereof;means for driving said roller; a grinding wheel; means for rotatablymounting and driving said grinding wheel; means for placing saidgrinding wheel in engagement with the body so as to grind the outersurface thereof; a bracket; means at one end of said bracket forpivotally mounting the same on said frame so as to be pivotable invarious directions; at least one half-shell of a bearing secured to theother end of said bracket and partly embracing said axle from above;means acting upon said bracket for pressing said half-shell upon saidaxle to press point and extending at a right angle to the axis the bodyupon said driving roller so as to be driven thereby; means forrestraining said bracket for moving in at least one direction about saidpivotable mounting means so that the body to be ground, aside fromrotating about its own axis, can move independently only in a circulardirection about the pivoting point of said bracket within a planepassing through said pivoting point and extending at a right angle tothe axis of the body, as well as about an axis lying within said planeand substantially connecting the axis to be ground with said pivotingpoint; eccentric means for reciprocating said bracket laterally aboutits pivoting point within a substantially horizontal plane; and meansfor arresting said lateral movement of said bracket in any positionwithin said horizontal plane.

9. Centerless grinding machine for grinding a substantially cylindricalbody having an axle protruding from said body comprising, incombination, a frame; a driving roller mounted substantiallyhorizontally on said frame and adapted to drive the cylindrical body byfrictional engagement therewith when the body is placed on top thereof;means for driving said roller; a grinding wheel; means for rotatablymounting and driving said grinding wheel; means for placing saidgrinding wheel in engagement with the body so as to grind the outersurface thereof; a bracket; means at one end of said bracket forpivotally mounting the same on said frame so as to be pivotable invarious directions; at least one half-shell of a bearing secured to theother end of said bracket and partly embracing said axle from above;means acting upon said bracket for pressing said half-shell upon saidaxle to press the body upon said driving roller so as to be driventhereby; means for restraining said bracket for moving in at least onedirection about said pivotable mounting means so that the body to beground, aside from rotating about its own axis, can move independentlyonly in a circular direction about the pivoting point of said bracketwithin a plane passing through said pivoting of the body, as well asabout an axis lying within said plane and substantially connecting theaxis to be ground with said pivoting point; eccentric means forpositively moving said bracket laterally about its pivoting point withina substantially horizontal plane; and electromagnetic means forarresting said lateral movement of said bracket in any position withinsaid horizontal plane.

References Cited in the file of this patent UNITED STATES PATENTS566,122 Ashton Aug. 18, 1896 1,779,618 Phelps Oct. 28, 1930 1,879,110Cramer Sept. 27, 1932. 2,012,716 Colchensky Aug. 27, 1935 2,039,223Hutchinson Apr. 28, 1936 2,045,894 Binns June 30, 1936 2,242,031 HjarpeMay 13, 1941 2,622,373 Stahlecker Dec. 23, 1952 FOREIGN PATENTS 838,572Germany May 8, 1952

